The \(n\) -th image position \(\theta _n\)  and the \(n\) -th image
magnification \(\mu _n\)  can be approximated as follows
[1]}, [2]},
<FIGURE><FIGURE>\(\theta _n=\theta ^0_n+\frac{u_{ps}(\beta -\theta _n^0)e^{\frac{\bar{b}-2n\pi }{\bar{a}}}D_{OS}}{\bar{a}D_{LS}D_{OL}},\) 
\(\mu _n=\frac{u_{ps}^2(1+e^{\frac{\bar{b}-2n\pi }{\bar{a}}})e^{\frac{\bar{b}-2n\pi }{\bar{a}}}D_{OS}}{\bar{a}\beta D_{LS}D_{OL}^2}.\) 
